If you do not have an “Add New” button, you will need to add your lead in as a “Contact,” a name for a lead that has been qualified as useful.
Although this is not strictly necessary, if the lead is an individual, Salesforce is most often used for Business to Business sales where there may be many different people in a company’s hierarchy that are associated with their business account. It is also a way to ensure that you are not trying to put a lead in that is already in the system. Scroll down the page that lists all the info you have for the account. Approximately halfway down the page there will be a list of “Contacts” for the business.
You will not need to add the account information, since it will automatically be linked to that Salesforce contact.
Alternatively, you can press “Save and New” to save the contact you have just created and add another new Salesforce contact to the account.